Electrowetting display devices are known. In an off state of a picture element of such a device an oil layer covers a display area. In an on state the oil layer is retracted so as to cover less of the display area. To switch the picture element to the on state a voltage is applied via an electrically conductive fluid immiscible with the oil. To switch the picture element to the off state, the voltage is switched off. In examples where the oil is coloured, a radiation beam passing through the picture element when in the off state passes through the oil and is imparted with colour. However, when the picture element is in the on state, the beam passes through less of the oil meaning its colour remains predominantly unchanged or more weakly imparted with colour.
When switching such a picture element from the off state to an on state, the oil layer may fragment to an undesired configuration. This fragmentation can reduce a quality of a display effect provided by the picture element, for example due to the radiation beam being inconsistently imparted with colour.
It is desirable to improve a display effect provided by an electrowetting element.